According to [0] the UK actually does not need to upgrade the network. I would also check [1] - the government task force that coordinates this. This is also interesting article: [2]. The company I work for is also engaged in a project that would allow using fleet of EVs as a power storage. (e.g. buying energy when it is cheap - during wind peaks and selling when it is expensive, but I dont know much about that project.)

[0] https://www.nationalgrid.com/stories/journey-to-net-zero/5-m... [1] https://www.lowcvp.org.uk/projects/electric-vehicle-energy-t... [2] https://www.wired.co.uk/article/electric-vehicle-car-infrast...